Thread: Scroll bar help

anonytmouse, anyone, im at a total lost to this scrollbar thing. I reviewed MSDN scrolling examples, i did wat i could, modified the codes, improved on the scroll position and max n min values but i still can't get the output of my bitmap icons correct. Someone pls advise.

Code:

static int xClient, yClient, Column, IconsNo, CurrentPos;
		case WM_SIZE:
			IconsNo = 13;
			Column = IconsNo / 4 + 1; // if possible correct this formula
            xClient = LOWORD (lParam) ;
            yClient = HIWORD (lParam) ; // this is what we wan
			si.cbSize = sizeof(si);
			si.fMask = SIF_RANGE | SIF_PAGE;
			si.nPage = yClient; // page/viewing size is Y coord, Reasonable rite
			si.nMin = 0;
			si.nMax = Column * 150 + 10 - yClient;
			SetScrollInfo(hwnd,SB_VERT,&si,TRUE);
		case WM_PAINT:
			HDC hdc;
			hdc = BeginPaint(hwnd,&ps);
			HBITMAP test;
			test = LoadBitmap(GetModuleHandle(NULL),MAKEINTRESOURCE(IDB_NOTE));
			int x,y,i;
			x = 10; y = 10; // starting coordinates
			i = 0;

			// Displaying the Icons onto the client area
			while(i<IconsNo)
			{
				if ( x > 265 ) 
				{
					x = 10;
					y = y + 90;
					bMp->Draw(test,hdc,1,x,y,0,0);
				}
				bMp->Draw(test,hdc,1,x,y,0,0);
				x = x + 85;
				i++;
			}

			if (Scroll )
			{
				HDC TempHDC;
				TempHDC = CreateCompatibleDC(hdc);
				SelectObject(TempHDC,test);
 // i did this SelectObject to show if scrolling worked
// but this bitmap will only appear if i did an extreme
// thumb position from down to up, other than it wun even appear
				BitBlt(ps.hdc,ps.rcPaint.left,ps.rcPaint.top,
					   ps.rcPaint.right - ps.rcPaint.left,
					   ps.rcPaint.bottom - ps.rcPaint.top,
					   TempHDC,
					   ps.rcPaint.left + 0,
					   ps.rcPaint.top + CurrentPos,SRCCOPY);
				Scroll = FALSE;
			}
			
			EndPaint(hwnd,&ps);
			DeleteObject(test);
			break;
	    case WM_VSCROLL:
			// coding this scroll bar is making my hair drop !
			int YnewPos,MovedAmt;
            si.cbSize = sizeof (si); // impt
            si.fMask  = SIF_ALL; // impt
			GetScrollInfo(hwnd,SB_VERT,&si);
			YnewPos = si.nPos;
			switch(LOWORD(wParam))
			{
		    	case SB_LINEDOWN:
					si.nPos +=5;
					break;
				case SB_PAGEDOWN:
					si.nPos += 20;
					break;
				case SB_THUMBPOSITION:
					si.nPos = si.nTrackPos;
					break;
				case SB_PAGEUP:
					si.nPos -= 20;
					break;
				case SB_LINEUP:
					si.nPos -=5;
					break;
			}
			if ( si.nPos != YnewPos )
			{
			    SetScrollInfo(hwnd,SB_VERT,&si,TRUE); // impt
			    GetScrollInfo(hwnd,SB_VERT,&si); // impt

			    Scroll = TRUE; // flag to inform WM_PAINT abt new job
			    MovedAmt = YnewPos - si.nPos; // determine scroll moved amt

                ScrollWindowEx(hwnd,0,MovedAmt,NULL,NULL,NULL,NULL,SW_INVALIDATE);
			    UpdateWindow(hwnd); // push WM_PAINT now
			}
		  break;

everithing abt the scrollbar is fine now, all i need is that it display the correct amount of icons being hidden below or above. This is what im stucked with.
Please take a look at my attached Image1. My variable IconsNo was set to 13, so there should be another Bitmap icon at the end of my scroll.
Ok, for now, let me get one thing straight first, do me(the programmer) have to take charge of all drawings to make up for the scrolling actions the user did ? or win32 will take care of it for me.